This invention relates, in general, to semiconductor integrated circuit technology and, in an illustrative embodiment, to integrated circuits that include bipolar or BiCMOS devices.
Many modern integrated circuits utilize both bipolar and MOSFET (e.g., CMOS, NMOS, or PMOS) devices on a single chip. Such integrated circuits (when they combine bipolar and CMOS) are often termed xe2x80x9cBiCMOSxe2x80x9d. Fabrication of BiCMOS (or even BiNMOS or BiPMOS) integrated circuits poses special problems for the process designer because certain process steps (e.g., heating, deposition, etching, etc.) that may facilitate formation of bipolar devices may adversely effect formation of MOS devices.
One common problem with integrated circuit fabrication is the unwanted growth of oxide, specifically around window devices. Suppressing or suspending oxide growth around the window area should improve the uniformity of the wafers containing these devices. However, current means of suppressing or suspending oxide growth involve using low temperature (450xc2x0 C.) during the wafer push into the furnace followed by high temperature (615xc2x0 C.) for emitter poly deposition. These techniques are flawed in that they decrease wafer throughput and shorten furnace lifetimes.
Those concerned with the development of integrated circuit technology have consistently sought improved methods of integrated circuit fabrication. In order to increase throughput and uniformity, it is desirable to discover new methods of suppressing or suspending oxide growth during circuit fabrication.
Accordingly, the present invention provides an integrated circuit with a nitrogen implanted emitter window.
The present invention also provides a method of making an integrated circuit with minimal oxide growth wherein nitrogen is implanted into the emitter window after the emitter window etch, but prior to emitter conductor deposition.